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Abstract

This study investigated heavy metals in crude oil-polluted soil and the remediation potentials of Heat-Stable Biocatalytic Remediation Cocktail (HBRC) called Garbage Enzyme and its residue (HBRCR). The Crude oil-contaminated soil sample was collected from Agbura Community, Yenagoa, Bayelsa State. HBRC was produced from three substances; water, fruit skin (orange, pineapple, watermelon, plantain and banana peels) and brown sugar in a ratio of 10: 3: 1 respectively. They were subjected to fermentation for 90 days. The soil sample was divided in to ten groups. Group 1 served as the control, Group 2 untreated while Groups 3 to 10 were given different treatments for 180 days. Heavy metals (Hg, Cr, Cd, Pb and Ni) concentrations were analyzed using an Atomic Absorption Spectrophotometer (AAS). Significant decreases at p0.05 of Hg, Cr, Cd, Pb and Ni were observed in groups 3 to 10 when compared to groups 1 and 2. Results obtained from the study revealed that there was a decrease in concentrations of various heavy metals. Hg concentrations in Groups 1 to 10 were reduced by 0.00%, 9.97%, 76.36%, 63.61%, 65.61%, 60.93%, 83.17%, 69.50%, 68.41% and 79.35% respectively. Similarly, Cr concentrations in Groups 1 to 10 were reduced by 19.73%, 11.78%, 96.05%, 36.17%, 51.79%, 74.45%, 92.09%, 55.07%, 85.12% and 80.70% respectively. Also, Cd concentrations in Groups 1 to 10 were reduced by 40.00%, 26.67%, 100.00%, 98.02%, 100.00%, 86.36%, 100.00%, 100.00%, 100.00% and 100.00% respectively. In like manner, Ni concentrations in Groups 1 to 10 were reduced by 18.52%, 33.68%, 45.48%, 69.55%, 47.11%, 44.05%, 51.05%, 64.57%, 65.49% and 65.41% respectively while Pb concentrations in Groups 1 to 10 were reduced by 8.09%, 3.32%, 48.05%, 55.74%, 60.77%, 55.32%, 100.00%, 41.25%, 100.00% and 63.54% respectively. The Results from this study showed that HBRC and HBRCR elicited significant removal of heavy metals from crude oil-contaminated soil and they could be used as remediation agents for heavy metals.